Four former Rwandan government ministers are on trial at a U-N war crimes tribunal in Arusha, Tanzania, charged with masterminding the 1994 genocide.

The spokesman for the U-N International Criminal Tribunal for Rwanda, Roland Amoussouga, says this is the first time ministers from the former government are having their cases heard as a group. Other ministers are or have been tried separately.

The four ministers are charged with nine counts each of genocide, conspiracy to commit genocide, public incitement to commit genocide, and other genocide-related charges, plus a charge of crimes against humanity.

The four men, who were part of Rwanda's interim government, have denied the charges.

Mr. Amoussouga says the prosecutors will try to prove the defendants conspired to carry out the genocide.

"They (prosecutors) are trying to establish that there was wide conspiracy to commit genocide and they promised to show evidence that will enable the ,court to find them guilty," he says.